Imho, (don't misunderstand me, I really like the plug-in very much) , the Nepheton sounds a bit more "clicky" and digital. The original 808 Snare is much more "round" or soft. The Clap sounds a bit more "splashy" on the original and the cymbal and hihat has a slightly softer feel. Last but not least I think the original Kick is still phatter.
Maybe we will hear some improvements in the sound on one of the next updates to come...

Btw. no sound processing was used on the loops. Only cut and normalization were done.

The Nepheton kick's frequency is lower. The sound of the original kick is more "round". The Neph kick has a very defined Frequency. The originl 808s kick seems to have more overtone. To me it sounds more full.

Yes exactly. In audio mostly everything is subjective because ears don't have a built in analyzer (well, would be nice sometimes...)
There's another developer (who I will not tell here )of a 303 clone who has built in switchable models with different characteristic of the 303 filter and oscillator so one can switch to the model he likes most. Wouldn't that be a nice feature in future versions of Nepheton?

Btw... I always wanted a plug in Version of MY 808, so unfortunately I'm quite picky about this

Exactly currect. Marshall Law's 808 sounds different from my 808 too. The truth is all 808's don't sound the same. I usually jude the sound of an 808 by not only the kick drum but also the tonal characteristics of the snare and most importantly, the tonal characteristics of the high hats and cymbal. I've heard some 808s with crappy sounding high hats and I've heard some with spectaular sounding crispy high hats. Some of the crispiest and best sounding 808 high hats and cymbals I ever heard came from a rap music production team formally known as "Beats by the Pound." I'd probably do anything to get samples of those hats!!!!!! I wish my 808 sounded like that. Nepheton on the other hand, is the best 808 emulation I've ever heard compared to the Drumstation and Rebirth.

Open that guy's comparison samples in a wave editor and you'll notice that the Neph waveforms look upside down. The attacks go negative first, unlike most 808's this makes the sound pluck instead of pound. The only sound that I've confirmed as being in phase is the clave. I also agree that the BD is too deep in pitch. Perhaps D16's 808 is modded. I speculate that the snare's body is phase inverted, but the skin noise isn't, making the snare sound less splashy and a bit weird. The circuits are uncannily emulated, but those circuits had untold variables. Maybe model randomization within rated tolerances but weighted towards center of spec should be a future option.

it doesn't matter if the wave starts going up or down. Take a mono source, invert the phase and the sound will still be the same. The energy in of the signal will also be the same. It's all a question of frequencies and levels. The "snappy" sound of the 808s snare is a noise. It will not interfere with the "body" sound wheter you invert it's phase or not.

Forget the kicks and clicks, the differences in the ride stick out most of all. It sounds absolutely different. I think that's the biggest improvement Nepheton needs. And it has nothing to do with differences between original 808s. According to D16's own comparison samples on the site, similar difference between their 808 and Nepheton too.